Submission #876846

#	Time	Username	Problem	Language	Result	Execution time	Memory
876846		Hacv16	Pipes (CEOI15_pipes)	C++17	0 / 100	297 ms	65536 KiB

pipes

#include <bits/stdc++.h>
using namespace std;

const int MAX = 2e6 + 15;
const int INF = 0x3f3f3f3f;

int n, m, pre[MAX], low[MAX], seen[MAX], timer;
vector<int> adj[MAX];
vector<pair<int, int>> bridges;

void dfs(int u, int p)
{
    seen[u] = true;
    pre[u] = low[u] = ++timer;

    for(auto v : adj[u])
    {
        if(v == p) continue;

        if(!seen[v])
        {
            dfs(v, u);
            low[u] = min(low[u], low[v]);
        }else{
            low[u] = min(low[u], pre[v]);
        }

        if(low[v] > pre[u]) bridges.emplace_back(u, v);
    }
}

int32_t main(void)
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> m;

    while(m--)
    {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    for(int i = 1; i <= n; i++)
        if(!seen[i]) dfs(i, i);

    for(auto [u, v] : bridges)
        cout << u << ' ' << v << '\n';
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10